Fig 1: PDE4B expression regulates cAMP levels and PDE4B inhibition decreases Th2 differentiation and increases Th17 differentiation in DCs. (A,B) Expression profile of PDE mRNA expression in (A) WT DCs; n = 7 and (B) ΔGnas DCs; n = 6. ND = not detected; data normalized to lowest-expressing detectable gene. (C) PDE4 isoform fold change in ΔGnas DCs compared to WT cells; n = 5–6. (D) Western blots and (E) densitometry of Gαs and PDE4B protein expression in WT and ΔGnas DCs; n = 4. (F) PDE activity in WT and ΔGnas DCs; n = 5–6. (G) PDE4B expression after treatment of WT DCs with the adenylyl cyclase inhibitor MDL-12,330A (10μM, 16 h); n = 3. (H) PDE4B expression in WT and ΔGnas DCs treated with a PKA inhibitor (PKI, 10 μM) for 24 h; n = 4. Data normalized to WT DMSO control. (I,J) Fold change in PDE4B expression after treatment of WT and ΔGnas DCs with (I) PGE2 (10μM, 24 h); n = 2-4, and (J) cAMP analogs CPT (non-selective, 50 μM, 24 h), 6MB (PKA-selective, 50 μM), and 8ME (Epac-selective, 50 μM) for 24 h; n = 3–5. Data normalized to WT vehicle control. (K,L) WT and ΔGnas DCs were treated with DMSO (vehicle control), Ro 20-1724 (pan-PDE4 inhibitor, 10 μM), or A33 (PDE4B-selective inhibitor, 10 μM) for 24 h before culturing with CD4+ OT-II T cells. (K) IL-4 secretion and (L) IL-17 A secretion from co-cultured T cells was quantified; n = 4. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.